1. Field of the Invention
The present invention relates to a marine propulsion system, especially a marine propulsion system provided with an engine.
2. Description of the Related Art
Conventionally, a marine propulsion device (a marine propulsion system) provided with an engine is known (see JP-A-Hei 9-263294, for instance). JP-A-Hei 9-263294 discloses a marine propulsion device provided with an engine and a power transmission mechanism that conveys the driving force of the engine to a propeller at a predetermined fixed reduction ratio. This marine propulsion device is configured to convey the driving force of the engine directly to the propeller via the power transmission mechanism, and is configured so that the propeller rotation frequency increases corresponding to the increase of the engine speed.
However, the marine propulsion device (marine propulsion system) disclosed in JP-A-Hei 9-263294 has a disadvantage in that it is difficult to improve the acceleration performance in the low speed range when the reduction ratio of the power transmission mechanism is configured to achieve the higher top speed. On the contrary, when the reduction ratio of the power transmission mechanism is configured to improve the acceleration performance in the low speed range, it has a disadvantage in that the higher top speed is difficult to achieve. Thus, the marine propulsion device disclosed in JP-A-Hei 9-263294 involves an issue that it is difficult to bring both the acceleration performance and the top speed closer to the performance desired by the boat driver.